It doesn’t appear to have occurred to the timid mainstream media, but something of a holy war for your backside is involved in the new SingaporeAir non-stop flights from Singapore to San Francisco which start on October 23.

They will use the current version of the Airbus A350-900, and your backside will actually fit in its economy seats for a flight which can last as long as 17 hours flying against headwinds in the direction of Singapore over a nominal shortest possible distance of 13,592 kilometres.

Singapore Airlines announced this service yesterday in response to United Airlines’ just launched non-stop service on the route using the Boeing 787-9.

Thus the world of increasingly frustrated and discomforted economy class flyers will have a head on, make that rear on, contest between the Airbus and Boeing medium sized latest tech twin engined airliners on the same route, and the differences between the service standards of SQ and UA will not be the whole story.

Both airlines have configured their main cabins at nine seats across, but the Boeing is narrower and was designed by the American planemaker at the outset to be a very civilised ‘Dreamliner’ with roomy eight across seats in economy.

When a ‘Dreamliner’ is flown in the nine across configuration, which is what most carriers do, or will do, the seating is the among the meanest and most miserable every flown in any jet since the successful restarting of the modern jet age late in 1958 with Boeing 707s.

This isn’t what Boeing intended, but it is the awful reality.

The only way to fit typical American or Australian adults and teenagers into a nine across 787 for a flight requiring heroic powers of endurance would involve surgery to reduce hip width. (This also applies to operations where 767s are fitted with eight across Y class seats, and A330s are flown nine across in economy class.)

Qantas has promised to compensate economy class passengers in its forthcoming 787-9 services with extra legroom. That will never be good enough, unless it is so generous that a passenger can swivel sideways to avoid raw bone pain in the hips.

The problem for 787 operators is that unless they screw their passengers where it hurts they will not get seat counts that reflect rising levels of demand that weren’t understood when the design was set in granite.

The industry (over time) has entered a period in which growth in numbers, and in the size of the average human who catches planes, have both exceeded the theoretical economic optimums of super efficient cabin configurations.

This contest, between efficiency goals and the pain and discomfort thresholds of customers, is going to be laid bare (or something like that) when SingaporeAir’s civilised A350s take on United’s more compact 787s, across business and premium economy classes of product as well as in standard economy class.

The SingaporeAir flights will offer a total 257 seats, United’s 252 seats. The overall dimensions of the A350-900 are slightly larger than those of the 787-9.

The Singapore carrier’s use of the A350-900 appears to be interim, as that jet is optimised for shorter routes than the non-stop to San Francisco. In 2018 it starts taking deliveries of the ultra long range A350-900 ULR and says they will be used for the much longer non-stop route between Singapore and Newark (for New York City) which the airline abandoned in 2013, as well as to Los Angeles, which is only slightly further than San Francisco, but can consume vital extra minutes in its even busier vectoring for a landing.

It has also said other cities in the US will get A350-900 ULR flights. In the 2020s Boeing will offer a larger ultra long range jet in the 777-9 and Airbus has informally mentioned the ULR potential of larger versions of the A350 and an upgraded A380.